Timmy, an 8-year-old male, presents to his family doctor with a progressively worsening sore throat of 2 day’s duration

Timmy, an 8-year-old male, presents to his family doctor with a progressively worsening sore throat of 2 day’s duration. His other symptoms consist of headache, malaise, loss of appetite, abnormal taste, soreness in his neck, and difficulty swallowing. He is particularly distressed by his sore throat. Physical exam reveals a temperature of 101.2 F, tender cervical lymphadnopathy, tonsillar swelling and exudate without any other symptoms. Timmy’s doctor orders a throat culture. The results come back and show he has gram-positive pathogenic bacteria, occurring in pairs or chains, and exhibits beta hemolysis on blood agar. In what ways does Timmy’s physical barriers protect him from acquiring pharyngeal infections?